British marines today launched attacks on Basra with troops entering towns on the southern outskirts of the city and reports of fighting near bridges to the west.

As bombing raids continued across Iraq, a British forces spokesman said that a ground operation was underway to the south-east of Basra and that troops were having "considerable" success in engaging Iraqi forces.

Group captain Al Lockwood said the resistance to the British raid had mainly come from paramilitary groups, although reports suggested that it had in fact been led by regular Iraqi forces.

Gp Capt Lockwood said the defence had been "disorganised" and that there appeared to be "no command and control" among the Iraqi fighters. Troops are reported to have captured more than 20 tanks and at least five prisoners of war, including high-ranking Iraqi officials. He claimed that the south-east of the city was now blocked off.

The Arab satellite television channel al-Jazeera, which has a correspondent in Basra, reported a 90-minute exchange of tank and artillery fire on Sunday near a bridge on the city's western edge.

Meanwhile, thousands of US marines also launched a push north from south-central Iraq in "seek and destroy" missions, trying to clear the route toward Baghdad that they have nicknamed "ambush alley". Marine infantry and tank units moved into previously unsecured areas, seeking to provoke attacks in order to locate Iraqi fighters.

Abdul-Baqi Saadoun, one of the ruling Ba'ath party's top leaders in southern Iraq, told al-Jazeera his fighters are "rushing to die or be martyred".

Speaking on the BBC's Breakfast with Frost programme, the chairman of the US joint chiefs of staff, David Myers, praised the British performance in Basra and claimed that the military strategy had already achieved several key successes.

He claimed that the military had succeeded in ensuring that Iraq has not yet suffered a major humanitarian catastrophe and in preventing scud missiles from being fired into neighbouring countries. By capturing Iraqi oil fields, he claimed that troops had averted the ecological catastrophe that could have been caused by uncontrolled oil fires.

Gen Myers said: "I don't know how long it's going to last. I've always said that the tough part is yet to come."

In what could prove to be an important step in the battle to win the hearts and minds of Iraqi citizens, the first United Nations aid convoy was due to leave Kuwait today carrying fresh water. It will be the latest in a growing number of humanitarian deliveries to the south of Iraq, with the largest stocks arriving on board the British landing ship Sir Galahad on Friday.

Iraq threatens more suicide missions

Iraq's vice president has threatened more suicide bombings against US and UK troops, following the death on Saturday of four US soldiers from a suicide bomb.

The suicide bombing, the first of the war in Iraq, killed four US soldiers north of Najaf as well as their driver.

The bomber, identified as Ali Jaafar al-Noamani, has been awarded two posthumous medals by Saddam Hussein, according to Iraqi state television.

The Iraqi vice president, Taha Yassin Ramadan, told a news conference that Ali Jaafar al-Noamani was a non-commissioned army officer and father of several children.

The US soldiers, members of the 1st Brigade, 3rd Infantry Division, were manning a checkpoint on Highway 9 north of Najaf when a taxi drew up and the driver signalled for help. When the soldiers approached the car it exploded.

Arab television station al-Jazeera had reported that the bombing was the work of the fedayeen, the pro-Saddam militia. American and British troops have been warned of the possibility of suicide attacks, with reports in the Arab media that the Iraqi leader has established training camps for such attacks.

Baghdad bombardment intensifies

In a series of what officials termed "key" strikes on Baghdad, satellite-guided bombs were dropped overnight on the main training ground of the fedayeen paramilitary forces and an intelligence complex that the American military said was being used to "direct military intelligence operations and to coordinate the oppression of internal opposition". Surface-to-air missile sites and a presidential palace were also targeted.

"The strike enhances the security of coalition air forces conducting missions over the capital city of Baghdad," the US military's combined forces air component command said in a statement.

There were blasts in Basra and the northern city of Mosul, according to the Arab satellite television station al-Jazeera. US and British warplanes launched bombing raids near Karbala, south of Baghdad, targeting Iraqi fuel storage depots. Wing Commander Andy Suddards, who led a British harrier raid on one of the depots, said one goal was to cut the fuel supply chain for republican guard tanks.

Cook calls for UK troop withdrawal

Criticism of Tony Blair intensified on the home front as former foreign secretary Robin Cook dramatically called on the prime minister to bring Britain's troops home from Iraq.

Mr Cook - whose resignation as Leader of the Commons was the most high-profile political protest against UK involvement in the war - denounced the campaign in Iraq as "bloody and unnecessary".

And he warned that Britain and America risked stoking up a "long-term legacy of hatred" for the west across the Arab and Muslim world.

Leaders of Amnesty International also attacked the war as they prepared to deliver a petition to Downing Street calling on the prime minister to abide by international law during the conflict in Iraq.

Neil Durkin, a spokesman for Amnesty, said: "Eleven to 12 days into the conflict and some of the fears that we were raising are worryingly enough coming true.

"We are seeing civilians being killed or injured and we have worries about the nature of the strikes and the bombs. Have they been properly targeted, were they discriminate or indiscriminate?"

But there was some comfort for the prime minister in a poll for the News of the World, which found that 84% of Britons are in favour of continuing the war until its objectives have been achieved.

Al-Qaida 'operating in Iraq'

A group of non-Iraqi Arabs belonging to terrorist network al-Qaida are operating in the Najaf and Kerbala regions of Iraq, according to a leading opposition group.

The exiled Iraqi National Congress (INC) claims that al-Qaida is acting on an agreement made between Osama Bin Laden and Saddam Hussein which would allow al-Qaida to take control of the area if they can defend it.

The INC also believes that the suicide bombing which killed four US soldiers in Najaf on Saturday morning involved members of the group.

Zaab Sethna, a member of the INC based in northern Iraq, said: "We have been told today by a source based in Iraqi intelligence in Baghdad that non-Iraqi Arabs affiliated with al Qaida are operating in these areas."

Iraqi air commander 'replaced'

The commander of Iraqi air defence forces in Baghdad has been replaced after Iraqi missiles went astray and hit the country's capital, Baghdad, said a spokesman for the prime minister, Tony Blair on Saturday.

The spokesman said the source of this information came from intelligence reports. He stopped short of saying that the missiles had been responsible for the deaths in a marketplace in Baghdad last night, but US and British officials had suggested earlier in the day that stray Iraqi missiles could be to blame.

Bodies of UK servicemen flown home

The bodies of 10 British servicemen killed in Iraq returned to the UK on an RAF plane on Saturday afternoon.

The plane carrying the servicemen touched down at Brize Norton airfield where the soldiers' families gathered outside the Oxfordshire base's main passenger terminal.

British soldier killed in 'friendly fire' attack

A British soldier was killed and two others badly injured in a suspected "friendly fire" incident near Basra, according to defence sources.

The British soldiers were thought to have been hit when an American A-10 "tankbuster" aircraft fired depleted uranium shells on two armoured vehicles yesterday afternoon. Three other soldiers were described as "walking wounded".

Twenty-three British soldiers have now died in the war on Iraq. The soldier who died would be the fifth Briton to die in a "blue on blue" incident. Only four have been killed by the enemy.